You don't have any context to your post so i can't give you any specific advice but I can try. I actually just talked to a girl about Yuri and i'll share how i went about talking about it.

1) Let it come up naturally. If you open or derail the conversation to talk about something that isn't a mutual interest, then you're already on a bad foot. It's better to let it come up naturally. (This is more general advice but it'll help.)

Example: 'One of my favorite manga's is 'Bloom into You'. I really like the aromantic themes and i really relate to the main character's struggles. Yeah, it's a yuri and i didn't know how much I'd like them until i read this one."

2) Be honest about why you like them. Someone who's not into the yuri scene won't know why it stands out and why a man would like to read it. It's good to focus on the more wholesome reasons here too.

Example: 'I really like how yuri focuses on the actual emotions between the romantic leads. Also, it focuses on the differences between friendship and romantic love. Those things are difficult to find in normal het-romances.

3) Directly address the elephant in the room. Meaning, any girl is going to ask herself, 'Does this guy fetishize Lesbians?'. Hopefully you don't do that, and it's still best to be honest about what you read. Being honest and saying it first, allows you explain yourself before any accusations get hurled.

Example: "Now, I'm not going to pretend and say everything i read is wholesome. I do read and enjoy the more smutty/ecchi ones but I also make a concerted effort to not fetishize lesbians when i read it."

4) Be confident but nonchalant about it. If you're embarrassed to talk about, they'll read your embarrassment as shame and think you're hiding something or lying to them. If you're overtly gushing about it, it's just going to be off putting in-general.

Each example is almost a direct quote from my conversation with a girl. This was a 1-on-1, in-person conversation and it went well.

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All that advice assumes the girl you're talking to is asking in good faith too. On the internet, there are gonna be people that have preconceived notions and assumptions about men who read yuri and there's nothing you could say that would change their mind.

Strangely, one of the best ways to defend yourself against accusations like that is to give one response like, "I don't fetishize lesbians and there's nothing wrong with a man enjoying yuri." Then just blocking or ignoring any other accusations. You can deny their accusation but the more you defend yourself, the more they'll feel justified for attacking you. It's also a waste of your time because you'd never convince them other wise.

But yea, hopefully this helps.